Mimeographic printing machine

Abstract

A mimeographic printing machine comprises a cylindrical drum rotatable with a stencil supported thereon, a lower pusher roller located under the cylindrical drum coactive with the cylindrical drum to hold a paper sheet therebetween, an inside pusher roller movably received in the cylindrical drum for pushing the cylindrical drum toward the lower pusher roller, a drive gear drivable for rotation with the cylindrical drum, a support arm pivotally received in the cylindrical drum; an intermediate gear supported on the support arm and meshing with the drive gear, and an inside pusher gear mounted on the drive shaft of the inside pusher roller and meshing with the intermediate gear for pushing, with rotating, the inside pusher roller against the inner circumferential surface of the cylindrical drum.

What is claimed is: 
     
       1. A mimeographic printing machine comprising: a frame:   a rotary cylindrical drum having outer and inner circumferential surfaces, said outer circumference surface being adapted to support a stencil thereon, and perforations for passage of ink, said cylindrical drum being rotatable on said frame with the stencil supported thereon;   ink supplying means situated inside said cylindrical drum;   a lower pusher roller rotatably supported on said frame under said cylindrical drum adapted to hold a paper sheet between said lower pusher roller and said cylindrical drum to move the paper sheet forwardly;   an inside pusher roller having a drive shaft, said inside pusher roller being movably retained in said cylindrical drum and contacting the inner circumferential surface of said cylindrical drum for pushing said cylindrical drum toward said lower pusher roller;   a drive gear driven for rotation together with said cylindrical drum;   a pivotable support arm disposed inside said cylindrical drum;   an intermediate gear mounted on said support arm and meshing with said drive gear, said intermediate gear being movable in a rotating direction of said drive gear in response to pivotal movement of said support arm; and   an inside pusher gear mounted on the drive shaft of said inside pusher roller and meshing with said intermediate gear, said inside pusher roller being pushed, while rotating, against the inner circumferential surface of said cylindrical drum.   
     
     
       2. A mimeographic printing machine according to claim 1, further comprising a lock device for locking said inside pusher roller against movement such that said cylindrical drum and said lower pusher roller are out of contact with each other even when said inside pusher roller is in contact with the inner circumferential surface of said cylindrical drum, said lock device being releasable from the locking of said inside pusher roller during printing. 
     
     
       3. A mimeographic printing machine according to claim 2, wherein said lock device includes a latch lever and an inner pusher level attached to said inside pusher roller engageable with said lever to prevent said inside pusher roller from downward pivotal movement. 
     
     
       4. A mimeographic printing machine according to claim 3, further comprising: a cam movable in response to rotation of said cylindrical drum; and   a cam follower mounted on said drive shaft of said inside pusher roller and resting on said cam,   said cam and said cam follower having a relationship such that during non-printing said cam raises said inside pusher roller via said cam follower to bring said inner pusher lever into and out of engagement with said latch lever.   
     
     
       5. A mimeographic printing machine according to claim 1, wherein said support arm is pivotally mounted on a center axis of said drive gear. 
     
     
       6. A mimeographic printing machine according to claim 2, further comprising means for detecting supply of the paper sheet to produce a detecting signal for allowing said lock device to release locking of said inside pusher roller. 
     
     
       7. A mimeographic printing machine according to claim 2, wherein when a trouble arises, said lock device is able to lock said inside pusher roller against movement so as not to contact the inner circumferential surface of said cylindrical drum.